Treadle mechanism



Dec. 7, 1943. A. EPPLER, JR

TREADLE MECHANISM 2 Sheets-Sheet i1 /NVE/V m5;

Filed Feb. 2, 1942 Dec. 7, 1943. EPPLER, JR 2.336.395

TREADLE MECHANISM Filed Feb. 2, 1942 2 Sheets-Sheet 2 Patented Dec. 7, 1943 2,336,395 TREADLE MECHANISM Andrew Eppler, Jr., Lynn, Mass, assignor to United Shoe Machinery Corporation, Flemington, N. 3., a corporation of New Jersey Application February 2, 1942, Serial No. 429,197

8 Claims.

This invention relates to mechanism by which, upon the actuation of a treadle or like lever, a member may be carried quickly into contact with supported work, and then by a shift of the lever from a primary to a secondary fulcrum, caused to apply to said work considerable pressure with relatively little effort on the part of the operator. It may effectively be utilized in connection With the clamped-work type of machines for operating upon shoe-soles. An object of the invention is to efiect the change of the fulcrum promptly, Without lost motion of the lever.

The above object, I achieve by combining with a treadle-lever, having a fulcrum member shiftable to alter the action upon the Work, two members, as a toothed wheel and a co-operatingdetent, one of which members is movable into engagement with the other to lock the fulcrum member against movement, and a shield normally preventing engagement of the locking members and being movable under the influence of the treadle-lever. This shield acts in its movement to produce engagement of the locking members. The engaging effect of the shield is positive and without lag, permitting the full movement of the treadle to be applied usefully. More specifically, the toothed wheel is rotatable with the fulcrum member and a locking detent engages the teeth, such engagement being normally prevented by the shield. A cam, or other operating means, carried by the shield forces the detent into engagement with the teeth of the wheel. An actuating member may directly receive the action of the cam and transmit it to the detent through a spring. This compensates for differences in the time of movement of the elements and accelerates the engagement of the detent.

I further provide for movement and retention of the treadle-lever with less effort on the part of the operator. This I accomplish by so arranging a spring, which maintains the primary fulcrum member and the treadle-lever yieldingly in their normal positions, that said primary member, in its movement under the influence of the treadle-lever to lock the secondary fulcrum memoer against movement, reduces the force exerted by the spring upon said treadle-lever. More specifically, a tension-spring is joined to a lever which furnishes the primary fulcrum and to a relatively fixed point, and, as this primary lever turns under the influence of the treadle-lever, it shortens the effective length of the lever-arm to which the spring is attached. Consequently, increase in the force exerted by the tensioned sprin tends to be balanced by the lessened leverage through which it acts, this leverage being at a minimum when the operator must maintain the pressure upon the work by holding down the treadle.

The accompanying drawings illustrate a particular one of the several forms which my invention may assume,

Fig. 1 being a broken side elevation of the improved treadle mechanism;

Fig. 2, a top plan view thereof; and

Fig. 3, a fragmentary elevation of the locking detent taken at the side opposite that of Fig. 1.

The invention is especially concerned with that type of treadle mechanism disclosed in Letters Patent of the United States No. 1,853,495, Bertrand, April 12, 1932. In this arrangement, there is a frame 10 upon which is pivoted a primary fulcrum-lever l2 and a secondary fulcrum-lever [4 for a treadle-lever I6, this treadle-lever having a foot-pad 18 to which the operator applies pressure. The primary lever l2 oscillates about a horizontal spindle 28, secured in the frame, said lever being held by a'spring 22 yieldably in the full-line position indicated in Fig. 1, as determined by a stop-screw 23. This spring later will be described in detail. The treadle-lever rests near its forward extremity upon a roll 24 rotatable upon the primary fulcrum-lever I2. The secondary fulcrum-lever I4 is pivoted at 26 upon the frame, the treadle-lever being pivoted to it at 23 near its rear extremity. Back of the pivot 28, the end of the treadle-lever acts upon a rod 30, through which such an unillustrated clamping member as that present in the well-known planet sole-rounding machine, is to be moved quickly into engagement with a blank supported upon a pattern, and then caused to apply greater pressure to retain the blank securely for the rounding operation. Initially, the secondary fulcrumlever is free to turn about its pivot 26, and the treadle-lever fulcrums upon the roll 24, so it has a short power-arm between the roll and the footpad 53, and a long work-arm between said roll and the rod 33. This gives the preliminary rapid elevation of the rod, which is desired.

To shift the fulcrum of the treadle-lever from the roll 24 to the pivot 28, the secondary fulcrum-lever it has at its forward end a gear-segment 32, meshing with a pinion 34, which, with a ratchet-wheel 36, is fast upon a shaft 38 journaled horizontally in the frame It. During the work-engaging movement of the clamp by the rod .33, the pinion turns the gear-segment idly, but when resistance is encountered on the initiation of clamping pressure, the primary fulcrum-- lever I2 is turned contraclockwise (Fig. 1) under the influence of the treadle-lever, the spring 22 yielding. In this movement, an arm 40 fast with the primary lever i 2 is swung to the left, any excess of travel, due to springing, being prevented by a stop-screw 4|, threaded into the frame and arranged for contact with the lever. At 42, this arm is joined to the end or head of a shield 44, oscillatable about the shaft 38. The edge of a peripheral portion 43 of the shield lies close to and receives contact of the point of a detent 48, pivoted about a stud 50 fixed in the frame. When the shield-portion passes from beneath the detent, as the arm 40 is turned by the yield of the primary fulcrum-lever, said detent is carried into engagement with the teeth of the ratchet-wheel 35. This looks the pinion 34, and therefore the segment 32 and the fulcrum-lever M, against movement, and the pivot 28 becomes the secondary fulcrum of the treadle-lever, which now has a long power-arm between the foot-pad l8 and the pivot 28, and a short power-arm between said pivot and the rod 39, providing for the heavy work-clamping pressure.

Taking u now the features peculiar to this invention, it has heretofore been customary to employ only a Spring to cause the engagement of the detent with the teeth of the ratchet-wheel upon release by the shield. This is a satisfactory arrangement, unless the treadle is very rapidly depressed, as may be the case with efiicient operators. Under these conditions, there may be a substantial lowering of the primary fulcrumlever before the detent is forced by the spring into contact with a tooth of the wheel, to stop the movement of the secondary fulcrum-lever about its pivot and establish the new fulcrum for the treadle-lever. There will thus be permitted treadle-movement, which should be causing the application of clamping pressure to the work and which is inefiective for this purpose. To With certainty lock the secondary fulcrum-lever M, as soon as the shield-portion 46 leaves the detent 48, I positively actuate said detent under the influence of the shield itself. Pivoted upon the stud 50 is an actuating member 68, which at one side is recessed to receive the detent 48, this also being pivoted upon the stud. Between the actuating member and the detent, at one side of the pivot, an expansion-spring 62 is interposed, this urging the tail 64 of the detent normally against a stopscrew 66 threaded through the actuating member. Said actuating member has rotatable upon it, below the stop-screw, a roll 63 lying initially in a cam-depression "Iii in the periphery of the shield.

With the roll in the depression, the point of the detent rests upon the shield just at the rear of the edge of the portion 46, considering the direction in which said shield is oscillated by the arm 58 when the primary fulcrum-lever l2 yields. As this yield occurs under the influence of the treadle-lever 1'5, the lever-movement is transmitted to the shield 49%, turning the depression 1! in the direction indicated by the arrow in Fig. 3. The roll is at once cammed positively up upon the cylindrical surface of the shield, carrying the point of the detentofi the edge of the shield, and into engagement with the teeth of the wheel 36. The secondary-fulcrum-lever i4 is thereby looked, as already described, to make it effective while the'yield of the primary fulcrum-lever continues. It will be seen that whatever may be the rate of depression of the treadle, there can be no delay in the engagement of the detent, because of the positive communication to -it of the treadlemovement, and the utilization of substantially the full travel of the treadle for the application of work-clamping pressure is insured. The spring 62, by its compressibility, not only avoids the necessity for exact agreement between the outward movement of the roll 68, when it leaves the depression 10, and the inward movement of the point of the detent, as released by the shield, but also increases the speed of engagement of the detent with the ratchet-teeth. This, because the spring is normally loaded and exerts its force to urge in the point of the detent, when this is released by the shield.

Reference has been made to the spring 22, which holds the primary fulcrum-lever l2 in its normal relation. As this spring is stressed during movement of the fulcrum-lever, it necessarily offers increasing resistance, which must be overcome by the operator in lowering the treadle. But the type of spring and its connections are such that, as its resistance grows greater, the effective length of the arm through which the lever 12 acts upon it decreases, as the point at which the spring is joined to the lever passes from the center, to the left in Fig. 1, and downwardly. Finally, as the foot-pad l8 reaches its lowermost position, indicated by dash lines in Fig. 1, at which the operator must retain it during the action of the machine upon the work, the length of the lever-arm and the force which the spring exerts upon the treadle are at a-minimum, so little effort on the part of the operator is required for this retention.

l laving described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. Treadle mechanism comprising a treadlelever, a shiftable fulcrum member for the treadlelever, two members one of which is movable into engagement with the other to lock the fulcrum member against movement, and a shield normally preventing engagement of the locking members and being movable under the influence of the treadle-lever, said shield acting in its movement to force the locking members into engagement.

'2. Treadle mechanism comprising a treadlelever, a shiftable fulcrum member for the treadle-lever, two members one of which is movable into engagement with the other to lock the fulcrum member against movement, an actuating member for the movable locking member, a spring interposed between the actuating member and said movable locking member, and a shield normally preventing engagement of the locking members and being movable under the influence of the treadle-lever, saidshield'contacting with the actuating member to move the locking member.

3. Treadle mechanism comprising a treadlelever, a shiftable fulcrum member for the lever, a toothed locking member movableunder the infiuence of the fulcrum member, a -lockin gdetent for engagement with the teeth of the locking member, a shield normally preventing engagement of the detent with the teeth and being movable under the influence of the treadle-lever, and means carried by the shield for forcing the detent into engagement with the teeth.

4:. Treadle mechanism, comprising a treadlelever, a shiftable fulcrum member for the lever, a toothed locking member movable under the influence of the fulcrum member, a movable actuating member, a detent movable by the actuating ,member into engagement with the teeth of the locking member, a spring through which the movement of the actuating member is transmitted to the detent, a shield normally preventing engagement of the detent with the teeth and movable under the influence of the treadle-lever, and means carried by the shield for moving the actuating member.

5. Treadle mechanism comprising a treadlelever, primary and secondary shiftable fulcrum members for the lever, a toothed wheel rotatable by the secondary fulcrum member, a locking detent for engagement with the teeth of the wheel, a shield normally preventing engagement of the detent with the teeth and being movable under the influence of the primary fulcrum member, and means carried by the shield for forcing the detent into engagement with the teeth.

6. Treadle mechanism comprising a treadlelever, primary and secondary shiftable fulcrum members for the lever, a toothed wheel rotatable by the secondary fulcrum member, a locking detent for engagement with the teeth of the wheel, a shield normally preventing engagement of the detent with the teeth and being movable under the influence of the primary fulcrum member, and a cam formed upon the shield for forcing the detent into engagement with the teeth.

7. Treadle mechanism comprising a treadlelever, primary and secondary shiftable fulcrum members for the treadle-lever, the primary member providing a lever-arm, movement of the primary member causing the secondary member to be locked against movement, and a spring maintaining said primary member and the treadlelever yieldably in their normal positions and so connected to the lever-arm that the primary member in its movement under the influence of the treadle-lever decreases the leverage through which the spring acts upon said treadle-lever and thereby reduces the force exerted by the sprin upon said treadle-lever.

8. Treadle mechanism comprising a treadlelever, primary and secondary levers furnishing fulcra for the treadle-lever, movement of the primary lever by the treadle-lever causing the sec ondary lever to be locked against movement, and a helical spring joined to the primary lever and to a relatively fixed point, the primary lever as it turns under the influence of the treadle-lever shortening the effective length of the lever-arm to which the spring is attached.

ANDREW EPPLER, JR. 

